One of the worlds hardest metals, the precious metal iridium starts melting at a temperature of 2450°c and is therefore very resistant to spark erosion. Iridium is found in NGK iridium spark plugs, which currently represent the highest-quality technological solution. They feature an iridium-alloy on the middle electrode welded on in a special process using laser. By using it, the service life is doubled on average in comparison to standard nickel spark plugs.
Glossary - I
